/* styles.css */
body {
    font-family: Arial, sans-serif;
}

.header {
    background-color: #333;
    color: white;
    padding: 10px 20px;
}

.logo {
    display: inline-block;
}

.top-nav {
    float: right;
}

.top-nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
}

.top-nav li {
    display: inline;
    margin-left: 10px;
}

.top-nav a {
    color: white;
    text-decoration: none;
}

.container {
    display: flex;
    min-height: calc(100vh - 50px); /* 减去 header 的高度 */
}

.sidebar {
    width: 200px;
    background-color: #f8f9fa;
    padding: 20px;
}

.nav {
    list-style-type: none;
    padding: 0;
}

.nav-item {
    position: relative;
}

.nav-link {
    display: block;
    padding: 10px;
    text-decoration: none;
    color: #333;
    background-color: transparent;
    transition: background-color 0.3s ease;
}

.nav-link:hover {
    background-color: #e9ecef;
}

.subnav {
    display: none;
    padding-left: 20px;
}

.subnav li {
    padding: 5px 0;
}

.subnav li a {
    color: #6c757d;
}

.subnav li a:hover {
    color: #007bff;
}

.arrow {
    float: right;
    transition: transform 0.3s ease;
}

.main {
    flex-grow: 1;
    padding: 20px;
}